A quantum dot light emitting diode display (QLED) is a new display technology based on organic light emitting displays. Different from other types of organic light emitting diodes, its electroluminescent structure is a quantum dot layer, and its principle is that electrons are injected into the quantum dot layer through an electron transport layer, holes are injected into the quantum dot layer through a hole transport layer, wherein these electrons and holes are recombined to emit light in the quantum dots. Compared with organic light emitting diode display devices, QLED has the advantages of narrow emission peak, high color saturation, and wide color gamut.
At present, there are some technical problems in the pixellation and full color display of QLED. The solutions include the methods of ink-jet printing, transfer printing, and micro contact printing. In the case of ink-jet printing method, the major difficulty lies in the fabricating of the quantum dot ink. Generally, the quantum dot ink is generally obtained by dispersing a quantum dot in an organic solvent. As the quantum dot is a nano particle, it is difficult to obtain a quantum dot ink with high viscosity, which leads to the difficulty in printing.